Honeybees show altruism not limited to human race

Tuesday

I shudder when I read of biological research that might cause people, especially politicians or late-night television hosts, to do a double take.

I shudder when I read of biological research that might cause people, especially politicians or late-night television hosts, to do a double take.

Some clever experiments by a colleague, Gene Robinson at the University of Illinois, provide an example. As reported in a recent issue of the Journal of Experimental Biology, Robinson and his colleagues tested hypotheses regarding the evolution of altruistic social behavior.

How do some species, including humans, live in societies of cooperating, altruistic individuals? To test ideas about sociality, the researchers treated some honeybees with cocaine.

Biologists have grappled with hypotheses about social behavior for many decades. Social insects, including ants, bees and wasps, provide handy models to test those ideas.

While coca plants likely produce cocaine in response to insect herbivory, what does one learn by giving it to a bunch of bees?

Robinson and colleagues suggest sociality arose in bees by gradual modification and intensification of a reward sensation associated with altruistic acts. For honeybees, such acts could be sharing food.

Humans and other mammals find performing altruistic acts pleasurable; we practice altruism and have a reward system associated with it.

But honeybees were not known to have brain-based reward sensations. If honeybees have no reward sensations, then we must reject the hypothesis that sociality evolves through intensifying sensations associated with altruism.

This is where the cocaine comes in.

Honeybees engage in exquisite altruism. When foragers find a particularly rich food source, they return to the hive and share the information with colony mates through intricate "waggle dances."

Forager honeybees treated with cocaine dance more, or engage in more altruistic behavior, presumably because the cocaine intensifies the reward sensations associated with that altruism.

Nonforagers given cocaine do not dance, suggesting the dance is not some out-of-control response to cocaine.

This work supports the hypothesis that sociality arose through change of reward centers associated with altruism. It provides new perspectives on social behavior in any animal, including us.

Steve Rissing is a biology professor at Ohio State University.

steverissing@hotmail.com

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